Thread tensioning device



Jan. 26, 1960 .1. w. 1. HEIJNIS 2,922,598

THREAD TENSIONING DEVICE Filed June 6, 1955 2 Sheets-Sheet 1 INVENTOR Jan. 26, 1960 J. w. l. HElJNlS THREAD TENSIONING DEVICE 2 Sheets-Shem 2 Filed June 6, 1955 INVENTOR J0me: Wd/ffi/Wd/Vjh/S BY w ATTORNEY running thread but unfortunately,

United States Patent 2,922,598 THREAD TENSIONING DEVICE James Watt Ijsbrand Heijnis, A f hgi .Neth rlands, as-

signor to American Enka Corporation, Enka, N.C., a corporation of Delaware This invention relates -.to thread or yarn tensioning devices and more particularly to devices which will impose a substantially constant drag on a running thread irrespective of the tension of the yarn entering the device.

In the art relating to the tensioning of yarns or threads various devices are known for the purpose of imparting drag or resistance to the thread. Usually these devices are employed in order to impose drag devices of the type heretofore knownhave been characterized by inability to maintain a constant resistance in the presence of differences in'the tension of the running thread. Thus most of the prior art drag devices actually tend to add drag in varying amounts to the existing tension rather than to establish a resistance at a predetermined level and maintain it there irrespective of variations in the tension of the thread entering the system.

It is an object of the present invention to overcome the difficulties ofprior art tensioning devices and to provide a device which will impose a constant drag on a running thread irrespective of variations in the tension of the thread coming to the device. v

It is proposed according to the present invention to employ elements defining a tortuous thread passageway and to mechanically interconnect the elements in such a way that they move tangentially relative to the direction of movement of the thread so that when an incoming thread tension is high the degree of tortuousness is reduced and the drag surface is decreased while the drag pressure is increased thus to maintain a constant overall effect on the thread.

Other objects and advantages of this invention will be apparent upon consideration of the following detailed description of several embodiments thereof in conjunction with the annexed drawings wherein:

Figure l is a perspective view of a thread tensioner according to the present invention;

a desired drag on a r Figure 2 is a view in side elevation of a somewhat modified version of the thread tensioner of Figure 1, the housing being removed for convenience of illustration; and

Figure 3 is a perspective view of another modified type of thread tensioner also shown with the housing removed for convenience of illustration.

Referring in detail to Figure l, the numeral 10 indicates a housing which is hollow and in which two brake shoes 11 and 12 are suspended on pivoted parallel links 13, 14, 15, 16, 17, 18, 19 and 20. The links 15 and 16 are pivoted at 21 to the top of the housing and the links 13 and 14 are similarly pivoted at 22. At the bottom of the housing pivots 23 and 24 accommodate pairs of links 17-18 and 19-20 respectively. The links are pivotally connected to the respective shoes. The facing surface of the brake shoes or elements 11 and 12 are provided with teeth 25 which are staggered so that they interdigitate more as the shoes 11 and 12 swing toward one another and less as the elements swing away from 2,922,598 Patented Jan. 26, 1960 one another. At one end of the housing there is provided an aperture at 26 through which thread is admitted to the drag device. This thread is led through a forked tooth 27 at the right hand end of the shoe 12 in between the teeth 25 which define a tortuous passageway coaxial with the aperture at 26 and normal to the axes 21 to 24 inclusive and then out through a notch in the tooth 28 at the left hand end of the shoe 11.

The suspension of the shoes 11 and 12 can perhaps be better understood by reference to Figure 2 in which the housing 10 is omitted for convenience of illustration. It can be seen that in addition to the parts already described there is a strap 29 interconnecting the pivot 30 for the links 15 and 16 to the pivot 31 for the links 19 and 20 so that movement of one causes movement of the other in the same direction along the axis of a thread passageway defined therebetween. It is to be understood that all of the links 13 to 20 inclusive are pivoted at both ends and are of equal length so that the space defined among the pivots is always a parallelogram. Thus, the shoes 11 and 12 are always in parallelism irrespective of the degree of arcuate or swinging movement which they may make both toward one another and along the axis of the thread passageway extending between the respective braking surfaces. It will be evident of course from the use of an interconnecting strap such as shown at 2,9 that the shoes 11, 12 always shift an equal amount and in the same direction longitudinally, as well as an equal amount but in opposite directions laterally.

With continued reference to Figure 2, it can be seen that a spring 32 is connected to the pivot 30 and acts to bias the pivot for movement in a counterclockwise direction about the pivot 21. This has a tendency to move the shoes together so that the teeth 25 are resiliently :biased toward maximum interdigitation. The spring 32 is mounted for adjustment of its tension. To this end the spring 32 is held at its end opposite to the end engaging the pivot 30 by an anchor pin 33 projecting diametrically through a threaded bolt 34 which is held in a threaded anchor collar 35. The collar 35 is attached to and projects from a shoe 36 which is mounted for arcuate movement in a slot 37. The shoe is provided with a set-screw 38 for locking it in a desired position of adjustment. A knurled head 39 is provided at the end of the bolt 34. It can be seen that by loosening the set screw 38 and moving the shoe 36 in the track 37 that the effective thrust of the spring 32 on the pivot 30 can be altered. In addition to that the number of coils of thespring 32 that are available to work may be changed by turning the bolt 34 to change the position of the pin 33 so that more or less .coils of the spring are included in the thrust pattern. While it is not shown in the drawing, the track 37 is intended to be mounted on an appropriate part of the housing such as an inner wall thereof.

In the arrangement of Figure l, the spring 40 is held by a bolt 41 similar to the bolt 34. Bolt 41 is held by a plate 42 which is secured to an arm 43. The arm 43 is adjustably mounted on the housing 10 and hence can be moved to impose greater or lesser tension on the links 15, 16 as may be required.

' It can now be seen that a thread entering the tensioner from the right as indicated in Figure 2 will pass through a tortuous passageway, the tortuousness of which is the function of the tension of the spring 32 against the tension of the thread. If the thread tension is very high, the shoes 11 and 12 will be moved apart, the path will become less tortuous and the area of the surface imposing a braking effect will decrease even though the pressure exerted by the spring 32 will increase. Thusthe total drag will remain constant. If the entering tension is low, spring 32 will bias the shoes together so that the interdigitation of the teeth 25 will increase and the drag surface will increase. This surface even with a smaller pressure will maintain a drag equal to that of the high pressure-small drag surface which results from high thread tensions. 7 p 1 InFigure 3 there is shown a modification. of the invention in which the members which define the tortuous passageway reduce the tortuousness of the passageway by moving toward rather than away fromone another. In this'case, pivoted links 44-and 45 are suspended from rods 46 and 47. At their lower ends, links 44 and 45 are pivoted at 48 and 49 and are interconnected by a strap 50 from which there project five cantilever rods 51. A pairof links 52 and 53 extend upwardly from pivots 54 and 55 to pivots '6 and 57. The pivots 56 and 57 are interconnected by a strap 58 from which five cautilever rods 59 project and extend toward the strap 50. These rods are parallel to the rods 51. An interconnecting member or strap 60 connects the pivot 49 to the end of a rod 59 which is similar to the other rods 59 except that it is coaxial with the pivot 56 and is not cantilever in that it is pivotally connected at 61 to the end of the piece60 opposite to the pivot at 49. A cable 62 extends from the pivot 49 over a sheave 63 to a weight 64. Between the @end of the cable 62 and the weight 64 there is interposed a coil spring 65. The weight 64 and the coil spring 65 tend to swing the links 44 and 45 clockwise about their pivots as viewed in Figure 3. This movement tends to rock the links 52 and 53 anticlockwise about their pivots with the effect of moving the rods 59 away from rods 51. If the thread is passed through the system as indicated in Figure 3, it will be seen that the further apart that the rods 59 are moved from the rods 51 the more tortuous will be the passageway and the more drag surface will be in contact with the thread. On the other hand, excessive entering tension of the thread tends to close the rods 59 toward the rods 51 thereby to reduce the overall drag surface. presented by the device.

In all species of the invention there is present the concept of normal pressure and braking surface being so correlated that when pressure increases it is exertedin a smaller braking surface and when the pressure decreases a larger braking surface is available.

Inasmuch'as other modifications will become apparent to those skilled in this art, it is intended that. the scope of thisin-vention be limited only to the extent set forth in the following claims.

What is claimed is:

1. A thread tensioning apparatus comprising first and second elements, said elements including co-acting braking surfaces defining therebetween a thread passageway through which thread is passed, the magnitude of the braking surfaces being a function of relative element position, means mountingsaid first element for swinging movement both toward, andv along the axis of said passageway, means mountingsaid second element for swinging movement both toward and along the axis of said passageway in parallelism with said first element, means interconnecting said elements whereby movement of one causes movement of the other in the same direction along the axis of said passageway, and means resiliently biasing said elements toward a maximum braking position to tensionthread passed through said passageway.

2. A thread tensioning apparatus as set forth in claim 1 and further comprising means for varying the tension of said biasing means.

3. A thread tensioning apparatus as set forth in claim 1 and further comprising means for altering the effective thrust of said biasing means.

4. A thread tensioning apparatus as set forth in claim 1 wherein said braking surfaces are formed by interdigitating teeth projecting from each of said elements.

5. A thread tensioning apparatus as set forth in claim 1 wherein said braking surfaces are formed by rods extending from each of said elements.

6. Thread tensioning apparatus comprising a first element, parallel links mounting said first element for swinging movement, a second element, parallel links mounting said second element for swinging movement in parallelism with said first element, a strap interconnecting said elements so that the movement of one will be tracked by a movement of the other, said elements including c0- acting means defining a tortuous thread passagewaythereamong normal to the axis of swing of said elements, the degree of tortuousness being a function of relative element position, and means acting on one of said elements resiliently to bias said elements toward the position of maximum tortuousness for tensioning thread running in said passageway.

7. Thread tensioning apparatus comprising a housing, a first element, parallel links mounting said first element for swinging movement, a second element, parallel links mounting said second element for swinging movement in parallelism with said first element, a strap interconnecting said elements so that movement of one tracks movement of the other, a thread guiding aperture in said housing, said elements including co-acting means defining a tortuous thread passageway thereamong normal to the axis of swing of said elements and coaxial with the axis of said aperture, the degree of tortuousness of said thread passageway being a function of relative element position, and means acting on one of said elements resiliently to bias the said elements toward the position of maximum tortuousness for tensioning thread running in said passageway.

References Cited in the file of this patent UNITED STATES PATENTS 7,064 Babbett Feb. 5, 1850 1,064,292 "Crawford June 10, 1913 2,160,763 Taylor et al. May 30, 1939 2,615,656 Te Strake Oct. 28, 1952 FOREIGN PATENTS v 545,845 France Aug. 2, 1922 195,301 Switzerland Apr. 1, 1938 741,807 Germany Nov. '17, 1943 

